My lines are NOT parallel.
Correct; Scott, but they are so close to parallel (as they would meet at a distance so far away) that your projected starting point is not a unique location. It appears that your pyramid size proposal can be demonstrated from any of these positions shown below. Any further NE and you start getting a slight gap.
and an enlargement
btw, the corner of Khafre's as connected to the corner of Khufu's only appears to be connecting to an enclosure wall due to the way the map's grid lines mesh with the pyramids baselines. Your diagram is rough; but somewhat fair, although your theory is unsound. In order for your theory to work Menkaure's pyramid has to be exactly half the baseline of Khafre's andKhufu's, which is not the case. Because of this size difference your theory is unsound; and the dimensions of the three pyramids at Giza could never have been derived from your proposal. See below; where your method dictates that Menkaure's pyramid must be half the base-length of the other two. Your saying that your lines "are NOT parallel"; and they're not, but this means that you did not use the method you say you did and are in fact rather moving the lines so they do match the pyramids. If we can just "move lines" like that so that they don't conform to the methodology then we can finagle "anything".